US5541920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for a delayed replace mechanism for a streaming packet modification engine
Assignee: Nortel Networks Ltd
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Filing: 1995-06-15
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Granted: 1996-07-30
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Expires: 2015-06-15
Abstract
Abstract A delayed replace mechanism for a streaming packet modification engine. The delayed replace mechanism allows for packet streaming where embedded fields within a data packet may be modified dependent upon fields following them within the data packet. Data to be forwarded is buffered through a data FIFO while marking fields that are to be replaced. Calculated replacement fields are stored in a replacement FIFO to be overwritten upon transmission from the packet streaming mechanism.
Inventors
- 👤 Richard Angle
- 👤 Geoffrey Ladwig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:40
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/90; H04L49/9084; H04L49/9057; H04L69/00; H04L69/12
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
139 words
A streaming data modification apparatus comprising: a packet modification engine coupled to receive a data packet wherein said data packet includes a plurality of data fields including an embedded field to be replaced with a modified field calculated based on data fields preceding and following said embedded field within said data packet; a data buffer coupled to receive said data packet from said packet modification engine, said packet modification engine marking a space in said data buffer for said modified field to replace said embedded field; a replace buffer coupled to receive said modified field from said packet modification engine; and packet transmission logic coupled to said data buffer and said replace buffer for transmitting said data packet, said transmission logic replacing said embedded field in said data buffer with said modified field from said replace buffer upon transmission.
Claim 2
Dependent Claim
139 words
A streaming data modification apparatus comprising: a packet modification engine coupled to receive a data packet wherein said data packet includes a plurality of data fields including an embedded field to be replaced with a modified field calculated based on data fields preceding and following said embedded field within said data packet; a data buffer coupled to receive said data packet from said packet modification engine, said packet modification engine marking a space in said data buffer for said modified field to replace said embedded field; a replace buffer coupled to receive said modified field from said packet modification engine; and packet transmission logic coupled to said data buffer and said replace buffer for transmitting said data packet, said transmission logic replacing said embedded field in said data buffer with said modified field from said replace buffer upon transmission.
Claim 3
Dependent Claim
25 words
The streaming data modification apparatus of claim 1 wherein said embedded field comprises a received checksum field and said modified field comprises a transmission checksum.
Claim 4
Dependent Claim
25 words
The streaming data modification apparatus of claim 1 wherein said data buffer and said replace buffer each respectively comprise a first in/first out (FIFO) buffer.
Claim 5
Dependent Claim
39 words
The streaming data modification apparatus of claim 3 wherein said packet transmission logic comprises multiplexing circuitry coupled for transmitting said data packet and said modified field, said multiplexing circuitry inserting said modified field in place of said embedded field.
Claim 6
Dependent Claim
40 words
The streaming data modification apparatus of claim 4 wherein said data buffer includes storage for an identifier for said embedded field, said identifier being provided to said multiplexing circuitry as a control signal to trigger transmission of said modified field.
Claim 7
Dependent Claim
32 words
The streaming data modification apparatus of claim 5 wherein said data packet comprises an internet protocol (IP) data packet having a header, said embedded field being a checksum determined by said header.
Claim 8
Dependent Claim
49 words
The streaming data modification apparatus of claim 1 wherein said data packet includes a plurality of embedded fields to be replaced by a plurality of modified fields in random order, said replace buffer comprising an array of static random access memory (SRAM) for storing said plurality of modified fields.
Claim 9
Dependent Claim
32 words
The streaming data modification apparatus of claim 7 wherein said data buffer includes storage for identifiers identifying said embedded fields and storage for addresses in said SRAM corresponding to said modified fields.
Claim 10
Independent Claim
73 words
A method of data packet streaming comprising the steps of: receiving a data packet, wherein said data packet includes a plurality of data fields including an embedded field to be replaced with a modified field; buffering said data packet in a data buffer; marking said embedded field in said data buffer; generating said modified field; transmitting said data packet; and upon transmitting said data packet, replacing said embedded field with said modified field.
Claim 11
Independent Claim
73 words
A method of data packet streaming comprising the steps of: receiving a data packet, wherein said data packet includes a plurality of data fields including an embedded field to be replaced with a modified field; buffering said data packet in a data buffer; marking said embedded field in said data buffer; generating said modified field; transmitting said data packet; and upon transmitting said data packet, replacing said embedded field with said modified field.
Claim 12
Dependent Claim
23 words
The method according to claim 9 further comprising the step of after said generating step, buffering said modified field in a replace buffer.
Claim 13
Dependent Claim
28 words
The method according to claim 10 wherein said marking step comprises the step of storing tag information in said data buffer indicating the presence of said embedded field.
Claim 14
Dependent Claim
30 words
The method according to claim 11 wherein said replacing step includes the step of providing said tag information to control circuitry for selecting said modified field from said replace buffer.
Claim 15
Dependent Claim
53 words
The method according to claim 12 wherein said transmitting step comprises the step of streaming said data packet out through multiplexing circuitry, and wherein said replacing step comprises the steps of said multiplexing circuitry responding to said tag information and selecting said modified field to overwrite said embedded field of said data packet.
Claim 16
Dependent Claim
81 words
The method according to claim 9 wherein said data packet includes a plurality embedded fields to be replaced by a plurality of corresponding modified fields in random order, said method further comprising the steps of: buffering said plurality of modified fields in a fast memory array wherein each of said modified fields has an address in said memory array; and storing in said data buffer said addresses for said plurality of modified fields corresponding to said embedded fields to be replaced.
Claim 17
Independent Claim
79 words
A apparatus for data packet streaming comprising: means for receiving a data packet, wherein said data packet includes a plurality of data fields including an embedded field to be replaced with a modified field; means for buffering said data packet; means for marking said embedded field in said means for buffering; means for calculating said modified field; means for transmitting said data packet; and means for, upon transmitting said data packet, replacing said embedded field with said modified field.
Claim 18
Independent Claim
79 words
A apparatus for data packet streaming comprising: means for receiving a data packet, wherein said data packet includes a plurality of data fields including an embedded field to be replaced with a modified field; means for buffering said data packet; means for marking said embedded field in said means for buffering; means for calculating said modified field; means for transmitting said data packet; and means for, upon transmitting said data packet, replacing said embedded field with said modified field.
Claim 19
Dependent Claim
13 words
The apparatus of claim 15 further comprising means for buffering said modified field.
Claim 20
Dependent Claim
21 words
The apparatus of claim 16 further comprising means for tagging said embedded field in said means for buffering said data packet.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-30 | 2000-01-29 | 2000-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-30 | 2004-01-29 | 2004-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-30 | 2008-01-29 | 2008-07-30 | $7700.00 | Window Closed / Lapsed |